Particle filled resinous product of improved appearance

ABSTRACT

Plastic surfacing material of the FOUNTAINHEAD® type having a bold and aesthetically pleasing appearance is achieved by the use TFR pigments, the latter of which are manufactured by orienting reflective flake pigments in a plastic substrate and grinding the substrate to a particulate material.

This application claims the benefit of U.S. Provisional Application No.60/038,544, filed on Feb. 28, 1997.

FIELD OF INVENTION

The present invention relates to improvements in decorative productsformed of particle filled resins, commonly available in the marketplaceunder the names of CORIAN™ (Dupont) and FOUNTAINHEAD® (InternationalPaper).

BACKGROUND

Products of the general character of the aforementioned CORIAN™ andFOUNTAINHEAD® products have been long known and are commonly availablesuch as for use as kitchen and bathroom surfaces. Broadly speaking,these materials are formed of particle filled resins, the most commonresins being polyesters and acrylates, and the fillers ranging widely,often used to give particular visual effects to the product. Many priorpatents directed to these types of products exist, bearing titles suchas "Resinous Product Simulating Onyx" in Schaefer U.S. Pat. No.3,396,067; "Filled Polymethylmethacrylate Article and Process for itsManufacture" in Duggins et al U.S. Pat. No. 3,827,933; "Process for theProduction of Marbleized Reinforced Polyacrylic Compositions" in MillerU.S. Pat. No. 3,663,493; "Thick, Cured Polymethylmethacrylate Articleand Process for its Preparation" in Slocum Re. 27,093; "Reinforced ResinCompositions" in Rees et al U.S. Pat. No. 3,789,051; "Use of AluminaTrihydrate in a Polymethylmethacrylate Article" in Duggins U.S. Pat. No.3,847,865, these being just a few examples of the many, many U.S.patents which exist in this field.

The aforementioned products have achieved remarkable commercial success,especially for tabletops and kitchen and bathroom surfaces, and arenormally available in a great variety of appearances. For example, theaforementioned FOUNTAINHEAD® product is a solid, non-porous surfacingmaterial available in a variety of colors and patterns which runthroughout its thickness, giving it a soft, deep translucent and naturalfeeling of warmth. Yet this material is tough and resists heat, stains,mildew and impact, and can be easily repaired if damaged. TheFOUNTAINHEAD® product line includes soft, neutral solid colors and"granite-like" patterns, as well as grays, black and whites.

Commonly used pigments in these products are composed of small particlesof inorganic compounds, often metallic oxides, which are roughlyspherical in shape. Other pigments are also sometimes used, as well asfillers and larger pieces of colored material to provide differentvisual effects. Alumina trihydrate (ATH) is often included as a fillerfor its particular fire-retardant properties.

Pearlescent buttons have been made for many years by injection moldingor the like, using pearlescent and iridescent pigments, and suchpigments have been used in other fields as well, such as in themanufacture of bowling balls.

Commercially available pigments of this type, called by various namessuch as opalescent, pearlescent, iridescent, interference andthermochromatic pigments, are used to give the products in which theyare used a sheen, reflectivity and three dimensional look, and it wouldbe desirable to be able to provide such an appearance in surfacingmaterials of the type with which the present invention is concerned, asbroadly described above. However, until the present time this has notbeen successful for a variety of reasons, including the fact that manyof such pigments, here referred to simply as "pearlescent", becomeburied in the body of the product so that their light reflectingproperties become lost.

In addition, these commonly available pearlescent pigments are shearsensitive so that their pearlescent effect is killed by the addition ofcommon opacifiers used in these products, such as titanium dioxide andATH.

SUMMARY OF INVENTION

It is, accordingly, an object of the present invention to overcomedeficiencies in the prior art, such as indicated above.

It is another object of the invention to provide a new "pearlescent"additive which, when used in the manufacture of aforementioned productsof the FOUNTAINHEAD® type, produce new, bold and aesthetically pleasingappearances.

It is a further object of the present invention to provide such asurfacing material of the FOUNTAINHEAD® type which incorporates suchimproved "pearlescent" particles, and which consequently have such anew, bold and aesthetically pleasing appearance.

Yet another object of the present invention is to provide a method ofmaking such improved pearlescent particles, hereinafter sometimes calledtranslucent fire retardant particles (TFRs).

And still a further object of the present invention is to provide aprocess using such TFR particles to produce a number of new, visuallyaesthetically pleasing patterns in the FOUNTAINHEAD®-type products.

These and other objects are achieved in accordance with the presentinvention by providing appropriate TFR particles each containingoriented pearlescent flakes. The TFR particles are then used in themanufacture of the final FOUNTAINHEAD®-type products.

DETAILED DESCRIPTION OF EMBODIMENTS

A preferred process for making the TFR particles involves mixingconventional plastic, preferably polyester although acrylics and otherpolymers can also be used, together with conventional fillers, commonlyused in the manufacture of FOUNTAINHEAD® and CORIAN™ type products,together with a particular commercially available pigment whichcomprises small mica flakes of about 5-50 μm having angstrom thicknessmetal oxide coatings on their surfaces, often TiO₂, which coated micaflakes are commonly used to make pearlescent products including buttonsand bowling balls. After the coated mica flakes, optional fillers,optional conventional pigments for color, and uncured plastic are mixedtogether to form the TFR composition, curing (preferably completecuring) of the plastic is carried out in such a way as to cause the micaflakes to become oriented in particular orientation patterns. Onepreferred way of accomplishing this orientation is to cast the mixtureof flakes and plastic, with or without fillers and other pigments, ontoa flat plate or belt and heat the mixture differentially, e.g. from thebottom through a metal conveyor belt on which the composition is cast,so as to cause the flakes to become oriented in generally oval patterns.

Regardless of how orientation of the flakes is carried out, the curedproduct, e.g. in solid ribbon form, is then ground to different particlesizes, to produce a granular TFR product, which translucent fireretardant particles are themselves used as an additive in themanufacture of the final FOUNTAINHEAD® type products. A key factor inobtaining the desired final product is the nature of the TFRs whichcontain the coated mica flakes become locally oriented in the samedirection, as use of the original coated mica flakes alone in themanufacture of the final product, without the intermediate manufactureof the TFRs will not give the desired results; the reason why flakes perse and alone do not produce a good final product is that in commercialproduction of the final product, the flakes do not orient in such a wayas to give the desired appearance.

A wide variety of product appearances can be provided according to thepresent invention: for example, using appropriate brown pigments,products having the appearance of burl wood are made which cannot bemade according to the prior art.

In the manufacture of the TFRs, it is desirable to grind the pearlescentflake-containing solidified ribbon to provide TFR particles ofreasonably large size, desirably on the order of at least 50 μm ofminimum dimension. There is no limit on the maximum size of such TFRs,except it is preferred that they be no larger than 5 cm in theirgreatest dimension; their size is also limited by the thickness of thefinal product which is conventionally made in thicknesses of one-halfand three-quarter inches. TFRs in any one final product can be providedin a variety of sizes simply by variable crushing of the cured ribbon.

In the manufacture of the final product, the TFRs in plural sizes,preferably at least two or three different sizes, are added to theconventional mix in amounts of up to 30-35% in mixes where ATH is aningredient as is preferred, or in an amounts up to about 60% where theproduct is ATH-free. It is preferred that small quantities of the coatedmica flake pigment also be added to the final mix, preferably in aquantity which is less than the quantity of the TFRs, e.g. up to 50% ofthe quantity of the TFRs, to provide a final product having a somewhatenhanced appearance. In the manufacture of the final product, the TFRsbecome randomly reoriented to provide the final product, which has asomewhat pearlescent appearance. However, it is preferred that thecomposition of the final decorative product be passed through a die toorient parallel to the plane of the resultant product whatever rawcoated flakes may be present in the composition.

The final product preferably contains about 50-60% ATH, including theATH present in the TFRs, and about 15-20% TFRs, and also preferablyabout 1-5% additional conventional pigment, most preferably pigment ofthe coated mica type. The additional pigment, preferably of the coatedmica type, gives a good background for the TFR particles.

In more detail, in the manufacture of the TFRs using the aforementionedcoated mica flakes, the presently preferred method is to form a firstmixture of pigments, hereinafter sometimes called a holomar pigmentformulation, then mix the holomar pigment formulation with resin andoptional filler, e.g. ATH, and then to continuously cast the compositionon a heated belt so that there is a thermal gradient. When heat isapplied upwardly from the heated belt, the coated mica flakes tend toorient in generally oval shaped patterns. When the cured ribbon isthereafter ground to different particle sizes to produce the differentparticle sized TFRs, and these TFRs are then used in the manufacture ofthe final product, the pigment alignment is such that the holomarpigments of the TFRs reflect light in many different planes which shiftas the frame of reference of the viewer changes.

The composition for making the TFRs can vary widely, and typicallycontains 30-95% (preferably 30-50%) curable resin, preferablythermosetting polyester or thermosetting acrylic syrup; 0-65%(preferably 45-65%) ATH; 0.7-50% (preferably 6-10%) holomar pigmentformulation as explained below; 0-40% (preferably 3-8%) methylmethacrylate monomer; and appropriate initiator and/or catalyst, e.g.0.2-3.5% methyl ethyl ketone peroxide and 0.01-0.1% of a 12% cobaltoctoate composition. The aforementioned holomar pigment formulation isformed of 15-100% of the commercially available coated mica flakes,0-20% black pigment, 0-20% of other standard colored pigments, 0-80% ofa diluent which is a preferably a thermoplastic (non-reactive)polyester, 0-80% of reactive resin which is preferably a thermosettablepolyester, and 0-5% of a wetting agent.

In the most preferred method, the aforementioned TFR composition,preferably initially without the holomar pigment formulation andcatalyst which are later metered in, is well mixed such as in a kneadingcontinuous mixer, and the final mixture is cast onto the heated belt onwhich the mixture is cured to a solid. The resultant solid ribbon passesto a hammer mill where it is crushed and then conveyor fed to agranulator and then to a three-roll mill with adjustable rollers so thatthe maximum size of the TFR particles can be controlled. The TFRparticles can either be separated to sizes such as by using screens andthen remixed according to what is desired, or it can be used as iswithout classification, preferably after removal of fines.

Some non-limitative examples of formations are given below.

A preferred composition for the manufacture of the TFR particlesconsists of approximately 48% ATH, approximately 44% thermosettablepolyester resin, approximately 7% of the holomar pigment formulation,and approximately 1% in total of methyl methacrylate monomer, catalystand initiator. One holomar pigment formulation for producing a sapphirecolor consists of about 30% of coated mica flake pigment, about 70% ofthermoplastic polyester as diluent, and less than 1% of black pigment. Asimilar holomar formulation, but without the black pigment, produces abronze/copper color. An olive-colored holomar formulation is formed ofapproximately 33% of the coated mica flakes, 18% black pigment and 48.5%non-reactive polyester as a diluent.

FOUNTAINHEAD® sheet product is made according to standard practice andstandard formulation, but to which is added, in three separate runs,respectively 15% of said TFR particles, 20% of said TFR particles and25% of said TFR particles, based on the total composition. The resultantFOUNTAINHEAD® sheet products contain respectively about 60%, 55% and 50%ATH, with the remainder in each case being predominantly the thermosetpolyester with relatively minor amounts of other materials as indicatedabove. The TFRs can also be used in the manufacture of shaped goods.

Suitable exemplary and non-limitative pigment formulation examples, inaddition to those set forth above, are set forth below:

EXAMPLE 1 Copper Colored Pigment for Making TFRs

70% thermosettable polyester resin

30% copper colored coated flakes (Mearlin Super Copper 9350Z)

EXAMPLE 1A Copper Colored Additional Pigment

70% non-reactive polyester diluent

30% copper colored coated flakes (Mearlin Super Copper 9350Z)

EXAMPLE 2 Bronze Colored Pigment for TFRs

70% thermosettable polyester resin

30% bronze colored coated flakes containing black pigment (Mearlin SuperBronze 9250Z)

EXAMPLE 2A Bronze Colored Additional Pigment

70% non-reactive polyester as diluent

30% Bronze color coated flakes containing black pigment (Mearlin SuperBronze 9250Z).

EXAMPLE 3 Biege Colored Pigment for TFRs

66.01% thermosettable polyester resin

29.70% shiny metallic colored coated flakes (Mearlin Super Sparkle9110S)

2.97% gold colored coated flakes (Mearlin Sparkle Gold 9212P)

1.00% wetting agent

0.30% dark brown color coated flakes (Mearlin Nu Antique Bronze 9240AB)

0.02% green pigment (Ferro Green 11-41057)

EXAMPLE 3A Biege Colored Additional Pigment

66.01% non reactive polyester as diluent

29.70% shiny metallic colored coated flakes (Mearlin Super Sparkle9110S)

2.97% gold colored coated flakes (Mearlin Sparkle Gold 9212P)

1.00% wetting agent

0.30% dark brown color coated flakes (Mearlin Nu Antique bronze 9240AB)

0.02% green pigment (Ferro Green 11-41057)

EXAMPLE 4 Dark Green Pigment for TFRs

48.50% thermosettable polyester resin

30.00% light sandy colored coated flakes with green hue (Mearlin Hi LiteSuper Green 9830Z)

18.00% black pigment (carbon black)

3.50% gold colored coated flakes (Mearlin Sparkle Gold 9212P)

EXAMPLE 4A Dark Green Additional Pigment

48.50% non reactive polyester as diluent

30.00% light sandy colored coated flakes with green hue (Mearlin Hi LiteSuper Green 9830Z)

18.00% black pigment (carbon black)

3.50% gold colored coated flakes (Mearlin Sparkle Gold 9212P)

The following non-limitative example is for the manufacture of the TFRS:

EXAMPLE 5

48.02% ATH

44.14% thermosettable polyester resin

6.67% TFR pigment, e.g. according to examples 1, 2, 3 or 4

0.90% catalyst

0.25% methymethacrylate monomer

0.03% cobalt octoate solution (12%)

The foregoing description of the specific embodiments will so fullyreveal the general nature of the invention that others can, by applyingcurrent knowledge, readily modify and/or adapt for various applicationssuch specific embodiments without its undue experimentation and withoutdeparting from the generic concept, and, therefore, such adaptations andmodifications should and are intended to be comprehended within themeaning and range of equivalents of the disclosed embodiments. Forexample, the surfacing materials of the present invention can be madeusing acrylic or acrylate polymers instead of polyester polymers. It isto be understood that the phraseology or terminology employed herein isfor the purpose of description and not of limitation. The means,materials, and steps for carrying out various disclosed functions maytake a variety of alternative forms without departing from theinvention.

Thus the expressions "means to . . . " and "means for . . . ", or anymethod step language, as may be found in the specification above and/orin the claims below, followed by a functional statement, are intended todefine and cover whatever structural, physical, chemical or electricalelement or structure, or whatever method step, which may now or in thefuture exist which carries out the recited function, whether or notprecisely equivalent to the embodiment or embodiments disclosed in thespecification above, i.e., other means or steps for carrying out thesame function can be used; and it is intended that such expressions begiven their broadest interpretation.

What is claimed is:
 1. A particulate "pearlescent" pigment for plasticproducts, comprising small hard resin particles of different sizescontaining pearlescent reflective flakes which are aligned in eachparticle with their flat surfaces generally parallel.
 2. The pigment ofclaim 1 wherein said hard resin particles of at least two differentsizes are formed by grinding from a large sheet in which said reflectiveflakes are oriented.
 3. The pigment of claim 1 having a minimumdimension of 5 μm.
 4. The pigment of claim 1 containing 30-95% curedresin; 0-65% alumina trihydrate; 0.7-50% pigment formulation; 0-40%polymerized methyl methacrylate; said pigment formulation being formedof 15-100% reflective coated mica flakes, 0-20% black pigment, 0-20%colored pigment, and 0-80% resin.
 5. The pigment of claim 4 containing30-50% of said cured resin, said cured resin being thermoset polyesteror thermoset acrylic; 45-65% of said alumina trihydrate; 6-10% of saidpigment formulation; and 3-8% of said polymerized methyl methacrylate.6. In a solid article for proving a solid surface wherein the articlecomprises a pigment filled hard plastic matrix, the improvement whereinsaid pigment comprises pearlescent pigment particles according toclaim
 1. 7. In a solid article for proving a solid surface wherein thearticle comprises a pigment filled hard plastic matrix, the improvementwherein said pigment comprises pearlescent pigment particles accordingto claim
 3. 8. In a solid article for proving a solid surface whereinthe article comprises a pigment filled hard plastic matrix, theimprovement wherein said pigment comprises pearlescent pigment particlesaccording to claim
 4. 9. In a solid article for proving a solid surfacewherein the article comprises a pigment filled hard plastic matrix, theimprovement wherein said pigment comprises pearlescent pigment particlesaccording to claim
 5. 10. The solid article of claim 6 furthercontaining at least one of (1) alumina trihydrate and (2) coatedreflective flakes oriented substantially parallel to surfaces of saidsurfacing material in an amount up to 5%.
 11. The solid article of claim10 in which the hard resin is acrylic or polyester.
 12. The solidarticle of claim 10 containing said coated reflective flakes orientedsubstantially parallel to surfaces of said surfacing material.
 13. Thesolid article of claim 10 containing both said (1) alumina trihydrateand said (2) coated reflective flakes oriented substantially parallel tosurfaces of said surfacing material.
 14. The solid article of claim 8further containing at least one of (1) alumina trihydrate and (2) coatedreflective flakes oriented substantially parallel to surfaces of saidsurfacing material in an amount up to 5%.
 15. The solid article of claim14 in which the hard resin is acrylic or polyester.
 16. The solidarticle of claim 14 containing said coated reflective flakes orientedsubstantially parallel to surfaces of said surfacing material.
 17. Thesolid article of claim 14 containing both said (1) alumina trihydrateand said (2) coated reflective flakes oriented substantially parallel tosurfaces of said surfacing material.